title: Cost-efficient speckle interferometry with plastic optical fiber for unobtrusive monitoring of human vital signs.
abstract: A cost-efficient plastic optical fiber (POF) system for unobtrusive monitoring of human vital signs is presented. The system is based on speckle interferometry. A laser diode is butt-coupled to the POF whose exit face projects speckle patterns onto a linear optical sensor array. Sequences of acquired speckle images are transformed into one-dimensional signals by using the phase-shifting method. The signals are analyzed by band-pass filtering and a Morlet-wavelet-based multiresolutional approach for the detection of cardiac and respiratory activities, respectively. The system is tested with 10 healthy nonhospitalized persons, lying supine on a mattress with the embedded POF. Experimental results are assessed statistically: precisions of 98.8% ± 1.5% and 97.9% ± 2.3%, sensitivities of 99.4% ± 0.6% and 95.3% ± 3%, and mean delays between interferometric detections and corresponding referential signals of 116.6 ± 55.5 and 1299.2 ± 437.3 ms for the heartbeat and respiration are obtained, respectively.
authors.affiliation: University of Maribor, Faculty of Civil Engineering, SI-2000 Maribor, Slovenia.
authors.forename: Peter
authors.initials: P
authors.lastname: Podbreznik
authors.forename: Denis
authors.initials: D
authors.lastname: Đonlagić
authors.forename: Dejan
authors.initials: D
authors.lastname: Lešnik
authors.forename: Boris
authors.initials: B
authors.lastname: Cigale
authors.forename: Damjan
authors.initials: D
authors.lastname: Zazula
mesh_terms: D000328:Adult; D001513:Beds; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation* / Q000379:methods; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007368:Interferometry / Q000295:instrumentation* / Q000379:methods; D008962:Models, Theoretical; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods; D055100:Optical Fibers; D015203:Reproducibility of Results; D012119:Respiration; D058067:Wavelet Analysis